At that time, because of Emperor Chongzhen at that time, he wanted to make peace, but because he couldn't pull his face down and because the matter of making peace was exposed, Chongzhen's idea of making peace was aborted. However, it is said that Chongzhen temporarily suppressed this matter, but he still wanted to make peace, so he said that he did not support Yue Fei's loyal opposition to the Qing Dynasty, so he had a very contradictory idea. In this case, the villain Qin Gui got in the way, and Zhang Jun chose to help Chongzhen kill Yue Fei for his own benefit, so as to gain his own interests.
So the reason why Zhang Jun framed Yue Fei at that time was mainly the meaning of Chongzhen at that time. He wants to please in front of Chongzhen. So after learning the meaning of Chongzhen, I helped Chongzhen frame Yue Fei so that he could kill Yue Fei. So to some extent, not only Zhang Jun can kill Yue Fei, but many people killed Yue Fei.
So at that time, Zhang Jun actually lived for his own interests. Not everyone lives for their beliefs or for the righteousness of their country.